Tech entrepreneurs are also concerned that the tariffs make it harder to invent the kinds of new products that drive US innovation.
Harley's stock fell as much as 7% during trading Monday.
The move is in response to new European Union tariffs that recently took effect.
Adding to the difficulty facing the company were steel and aluminum tariffs on the EU, Canada and Mexico finalized by the Trump administration at the start of June.
At the White House as he boarded the presidential helicopter he had ignored questions on the topic. Speaker Ryan, who is set to retire at the end of the year, is not a fan of Trump's tariffs and has spoken out against the trade war.
Trump has brushed aside those criticisms, vowing that the US has been taken advantage of so badly in the past that it can not lose a trade war.
The president's tweet references statements made by Harley Davidson as to why they planned to move some production in their company to an global location. That's expected to add up to a burden of $90 million to $100 million annually, which Harley-Davidson will absorb rather than pass extra costs on to customers. In fact, his policies may play a role moving them to the very country he wanted to defend the company against. In January, it said it would consolidate its Kansas City, Missouri, plant into its York, Pennsylvania, facility.
Executives in Harley-Davidson were among the first to visit the White House in February 2017 shortly after Trump took office.
It's not like Harley-Davidson only manufactures its products in the USA right now, though.
"I think this is only the beginning".
Trump has held up Harley as an example of a manufacturer that would benefit from his policies.
Harley-Davidson Inc. said that it will not raise its prices due to "an immediate and lasting detrimental impact to its business in the region". Overseas sales also have been stalling. "Does Harley even understand what "Made in America" means?" He called the plan the "latest slap in the face to the loyal, highly skilled work force" that builds the company's bikes.
Harley has warned consistently against tariffs, saying they would negatively impact sales.
"Harley-Davidson maintains a strong commitment to US-based manufacturing which is valued by riders globally".
The company's brand derives from USA manufacturing and if it wants to keep its iconic status, "it needs to focus on United States production", said spokesman Tony Montana. By driving up the company's costs, Trump's tariffs are making it almost impossible for the 500-worker company to compete with cheap nails from China, Skarich said. Analysts project the company will earn about US$587m this year on US$5b of revenue.
Harley estimated that ramping up output in worldwide plants for the European Union may take at least nine to 18 months.
The company sold about 40,000 new motorbikes a year ago in Europe, equivalent to a sixth of its worldwide sales, making the region its most important market after its home country.